In the semiconductor manufacturing industry, a semiconductor wafer is typically processed in various differing processing environments in order to achieve desired electrical characteristics on the wafer. Conventionally, the wafer is transported between processing environments through one or more load lock chambers, wherein the load lock chambers substantially isolate the different processing environments from one another by substantially evacuating the load lock chambers of processing gases once the wafer is inserted therein. Such isolation of the processing environments via the load lock chambers helps to minimize cross-contamination between the processing environments.
Conventionally, a load lock chamber is coupled to a process chamber, such as a process chamber for an ion implantation system. FIG. 1 illustrates an exemplary conventional processing system 10, wherein a load lock chamber 15 is coupled to a process chamber 20 via a first gate valve 25. The first gate valve 25 selectively isolates a process environment 30 within the process chamber 20 from a load lock environment 35 within the load lock chamber 15. A second gate valve 40 is disposed opposite the first gate valve 25, wherein the second gate valve selectively isolates the load lock environment 35 from an external environment 45 (e.g., atmosphere). Typically, the load lock chamber further comprises one or more ports 50 that selectively permit an evacuation or venting of the load lock environment 35, depending on whether a wafer 55 is being transferred between the external environment 45 and the load lock environment 35, or between the load lock environment and the process environment 30.
One problem with the conventional load lock chamber 15 is that contamination particles 60 may be present within the load lock environment 35, wherein upon evacuation or venting through the one or more ports 50, the contamination particles may be moved onto a surface 65 of the wafer 55. Such contamination particles 60 on the surface 65 of the wafer 55 can have deleterious effects on the subsequent processing of the wafer, thus leading to potential production losses. For example, the location of the one or more ports 50 and wafer 55 may lead to turbulent flows within the load lock environment 35, thus dispersing the contaminant particles 60 about the surface 65 of the wafer 55.
Further, various pre-processing procedures are typically performed prior to the wafer 55 being transferred into the process environment 30. Such pre-processing procedures may comprise a notch alignment procedure, wherein the wafer 55 is aligned in a predetermined manner, an identification of the wafer by reading of a barcode (not shown) on a backside 70 of the wafer, or various other pre-processing such as a heating or cooling of the wafer prior to, or after, the wafer is transferred into or out of the process environment 30. Typically, each pre-processing procedure on the wafer 55 is performed in a respective pre-processing station 75, wherein the wafer is transferred from one pre-processing station to another, and then into the load lock chamber 15. Such conventional pre-processing of the wafer 55 can take a significant amount of time, as identifying and/or positioning of the wafer, as well as transferring the wafer between each pre-processing station typically occurs prior to the wafer entering the load lock chamber 15.
Therefore, it is desirable to provide an improved load lock apparatus, wherein contamination to the wafer is significantly decreased, while also allowing various pre-processing procedures to be performed from within the load lock apparatus, thus increasing overall production efficiencies.